In testing semiconductor devices such as ICs and LSIs by automatic test equipment (ATE) or an IC tester, a semiconductor IC device to be tested is provided with test signals or test patterns produced by an IC tester at its appropriate pins at predetermined test timings. The IC tester receives output signals from the IC device under test in response to the test signals. The output signals are strobed or sampled by strobe signals generated by the IC tester with predetermined timings to be compared with expected data to determine whether the IC device functions correctly or not. Typically, timings of the test signals and strobe signals are defined relative to a start timing of each test cycle of IC tester.
As noted above, an IC tester generates test patterns and strobes, i.e., test vector, based on digital test vector data described in a language (format) unique to the tester. Such languages for automatic test equipment are different from manufacturer to manufacturer.
Recently, IEEE has proposed a test language STIL (Standard Test Interface Language) as a standard test interface language (IEEE Std 1450-1999). STIL provides an interface between computer-aided engineering (CAE) such as a logic test simulator and automatic test equipment. In a CAE environment or an EDA (electronic design automation) environment, a semiconductor device is designed with the aid of computer system and such design is tested through a logic test simulator or a testbench. It is preferable to utilize the digital test vectors resulted from the logic simulation in testing actual semiconductor devices by IC testers. STIL is designed to facilitate the transfer of large volumes of digital test vectors from CAE environment to the automatic test equipment (ATE) environment.
The STIL test language has recently become a standard. At present, however, most ATE systems do not use STIL as a native language. Such native languages provided by test equipment manufacturers are not compatible to one another. Accordingly, there is a need to effectively convert STIL to the ATE native language.